Medium severity · published Aug 12, 2026
CVE-2026-19643
Out-of-bounds read in the Base64 decoder in Amazon aws-sdk-cpp on signed-char platforms
5.3
CVSS
0.6%
EPSS
No
On KEV
Description
An out-of-bounds read issue in the Base64 decoder in Amazon aws-sdk-cpp before 1.11.862, on some platforms, might allow a remote authenticated user to crash an application that processes crafted Base64-encoded input.
To remediate this issue, users should upgrade to version 1.11.862.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
High
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 47% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AW
aws-sdk-cpp · AWS
through 1.11.861 · source: vendor
AS
Aws Software Development Kit · Amazon
before 1.11.862 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-19643
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-19643
Vendor Advisory
https://aws.amazon.com/security/security-bulletins/2026-080-aws/
Release Notes
https://github.com/aws/aws-sdk-cpp/releases/tag/1.11.862
Vendor Advisory
https://github.com/aws/aws-sdk-cpp/security/advisories/GHSA-mxm9-xpf9-x66x
More from aws-sdk-cpp
5.9
CVE-2026-19642
Out-of-bounds write in the Base64 decoder in Amazon aws-sdk-cpp